The present invention relates to electrically energized electromagnetically actuated valves for service in appliances such as, for example, ice makers employed in household refrigerators. Valves of the aforesaid type are required to operate with a low wattage power consumption and to be compact and inexpensive to manufacture. In particular, electrically energized solenoid-actuated valve employed for use in refrigerator ice makers are required to provide long life when connected to water supplies of varying impurity and chemical content.
Heretofore, electrically operated valves for refrigerator ice makers have employed a solenoid actuated poppet and a valving chamber which is formed of plastic material to prevent corrosion and malfunction of the valve by build up of foreign matter in the valving chamber.
Appliance water inlet valves having the valving chamber formed of plastic material generally have the whole valve body formed of plastic material for simplicity and economy of manufacturing. Plastic bodied valves of this type which are solenoid actuated pose particular problems in design in manufacturing in providing for attachment of the water inlet line fittings to the plastic valve body.
Furthermore complications have arisen in attaching the iron-base magnetic pole pieces, coil and armature mechanism of the solenoid to the plastic valve body for enabling electrical actuation and opening of the valve by magnetomotive force means. It has also been found difficult to provide an easily attachable metal structure in the plastic valve body for attaching thereto metal tube fittings for connection of the water supply line to the valve. Where a metal tube-receiving insert is molded onto the plastic valve body, the torque required to effect a seal, upon attachment of a metal tube to the valve, has resulted in damage to the valve body by the reaction to the torque applied to the metal insert. Furthermore, it has been found to be quite costly in manufacturing to preplace a metal insert in each mold cavity for molding a plastic valve body around the insert. Therefore, it has long been desired to fine a way or means of providing for metal inserts in a plastic bodied valve for enabling attachment of metal tube fittings thereto without the necessity of molding a metal insert into the plastic valve body.
It is known to provide a valve mounting bracket attached to the exterior of a plastic valve body which bracket inter-engages portions of a metal insert molded in the body for absorbing the torque of installation of a metal tube fitting onto the insert. However, this technique has not eliminated the need for molding the insert into the body. An alternate known expedient for attaching a metal insert onto the plastic valve body has been to provide a blind sealing threaded engagement between the plastic valve body and the metal insert. However, this technique has proven to be costly in the manufacture of the valve because threads must either be molded or machined into the plastic valve body and onto the metal insert, thereby increasing the manufacturing cost of the two components.
Therefore, it has long been described to provide a way or means of engagement of a metal insert onto the plastic valve body in a manner which eliminates molding or threaded connections and yet provides a fluid pressure tight seal.
In another aspect of the manufacture of electrically actuated appliance water inlet valves, theferro magnetic armature employed to effect opening of the valve must be movable within the valving chamber and yet isolated from the coil in order to maintain fluid tight integrity of the valving chamber. Known technique for providing assembly of such an arrangement have employed a non-metallic armature guide member received over the armature for guiding movement thereof during the valve opening and closing stroke. In the prior known valves, the armature guide is sealed onto the plastic valve body and retained against the forces of fluid pressure acting thereon by the coil and pole frame assembly. This sealing and retention technique of the armature guide member has resulted in costly mechanical fasteners received through the pole frame members and requires threadedly engaging the valve body with such fasteners in a manner sufficient to restrain the armature guide member against the force of the fluid pressure acting thereon. This known technique has required complete assembly of the armature, armature guide, coil and mounting frame members simultaneously during the manufacturing operation and has proven to be a costly and difficult to manage procedure with respect to concentric alignment of all the parts during production assembly. The conentricity problem is particularly complicated in view of the close sliding clearances between the armature and the guide needed to provide precise alignment of the armature for effecting reliable and repeatable valve operation.
The aforesaid tenchinque thus requires complete assembly of the valve before the valving cavity seal can be fluid pressure tested for sealing integrity which can result in rejection for seal failure at a more costly point in the manufacturing sequence.
Another problem encountered with known solenoid operated appliance water valves has been the problem of predetermining the flow rate of the valve, particularly where the valve has employed an elastomeric flow control washer which operates by pressure deformation in a precisely configured cavity. Heretofore, the flow rate of the valve having the flow washer encased therein could not be verified unit the valve was completely assembled. Consequently if the valve body was enclosed by non-metallic weldment at final assembly, in the event the flow washer did not funciton properly in the precision cavity to provide the required flow in the face of varying inlet pressure upon final testing. it was necessary to scrap the completed valve.
Thus, it has long been desired in the manufacture of a solenoid operated appliance water valve, to find a way or means of pre-assembling the armature and armatureguide onto the plastic valve body and sealing and retaining the sub-assembly thereof onto the valve body in operations separate from the assemblage of the coil and pole frame members there.
It has further been desired to find an inexpensive way of flow testing a flow control washer for use in a valve in its containment cavity without the necessity of completing the valve assembly.